Selenium-Enriched Cerium Oxidative Nanoplatform for Colorectal Tumor Surgery with the Guidance of NIR II Fluorescent Bioimaging and Tumor-Microenvironment Triggered Synergistic Therapy

Colorectal cancer (CRC) is the second most fatal and the third most common malignancy globally, posing a substantial challenge in malignant tumor therapy. To solve this issue, we introduce a novel Ce-Se oxide nanovesicle that incorporates indocyanine green (ICG) (Ce-Se&I). Upon surface modification with RGD (Ce-Se&IR), this advanced nanoplatform exhibits precise tumor targeting and is able to activate to produce potent reactive oxygen species (ROS) under tumor microenvironments with acidic and high-H₂O₂ conditions. Enhanced in vivo fluorescent bioimaging, with higher tumor-to-background ratios, allows for the accurate delineation of tumor boundaries from healthy tissue. Guided by second-near-infrared region (NIR II, 1000-1700 nm) luminescence imaging, tumors are entirely removed, resulting in minimal in situ tumor recurrence or multiorgan metastasis within 30 days postsurgery. Furthermore, with 808 nm laser illumination, the nanoplatform demonstrates a satisfactory photothermal conversion ability, which induces localized tumor thermal and further enhances ROS generation through the synergistic action of bimetallic ions, facilitating CRC cell destruction. These findings highlight the promising potential of Ce-Se oxide nanocomposites with tumor-microenvironment stimuli as a fluorescence bioimaging contrast agent and oxidative therapy nanoagent for cancer eradication, particularly under laser activation.